Currently there are only about 50 remaining individuals of this species. Lepilemur septentrionalishas been observed to have undergone a population reduction of ≥80% over the past 21 years (three generations, assuming a generation length of 7 years) due primarily to continuing decline in the area of occupancy, the extent of occurrence, the quality of habitat, and exploitation through unsustainable levels of hunting. This cause has not ceased, and will to a large extent not be easily reversible. A future population reduction of ≥80% over a 21 year period is also suspected due to the same cause. The area of occupancy ofL. septentrionaliscovers less than 10 km2. Its geographic range is severely fragmented and is undergoing continuing decline in area and quality of habitat. The number of subpopulations and mature individuals is also known to be in decline. Based on these premises, the species is listed as Critically Endangered.

This species occurs in Madagascar's far northern regions, north of the Irodo River, where it is now believed to be restricted to the extremely limited remaining patches of forest near the villages of Madirobe and Ankarongana in the Sahafary region. It was formerly believed to inhabit both dry and humid forests from the Montagne d' Ambre region south to the Mahavavy River near Ambilobe in the west, and probably to the Fanambana River south of Vohémar in the east. However, with the recognition of L. ankaranensis as a distinct species, the range of L. septentrionalis was reduced to a handful of very small remnant forest patches (Mittermeier et al. 2010 and references therein).The species area of occupancy (AOO) is restricted to less than 10 km2.

The major threat is forest loss due to Eucalyptus plantations, firewood, and charcoal production. The species is sometimes illegally hunted for food as well. The Andrahona Forest where it occurs is considered sacred but is tiny, riddled with trails and exploited for saplings, which are used in local construction. Socio-economic studies are underway to determine the anthropogenic effect on the remaining population.

This species is listed on Appendix I of CITES. This species exists only as small populations in the Sahafary region and is not in any protected areas. One of the most geographically restricted and least protected of all lemurs. It is uncertain whether any of the forest patches in which it occurs would be of sufficient size for protected area status. The species was listed as one of the world's 25 Most endangered primates in 2008 (Ravaorimanana et al., 2009). This is a species on the verge of extinction, and in need of special attention. This could include a last-ditch effort to save a piece of remaining habitat, with the Andrahona Forest perhaps presenting the best opportunity. Another option may be to undertake a captive breeding program, although members of the genus Lepilemur have always proven difficult to keep in zoos. It is possible that the sportive lemur in Montagne des Français is L. septentrionalis; if so, the prospects for this species' survival would be greatly improved. A survey and genetic study there is urgently needed.